Guide to the Ishikawa Diagram in Project Management

Guide to the Ishikawa Diagram in Project Management

By Henri Gisclard-Biondi
Published: 03/08/2021

The Ishikawa diagram, also known as a fishbone diagram, is a useful tool in project management, particularly when it comes to quality control.

Conducting a proper risk analysis, anticipating and solving problems are essential management skills to lead successful projects. These aspects should be taken into account as soon as the project planning phase begins. Luckily, presenting the root causes of a challenge and the ways to overcome it is the very purpose of a fishbone diagram.

Learn more about the Ishikawa diagram, how it’s used in project management and how to build your own! A free fishbone diagram template is also included to serve as an example and help you start your projects on the right track. Let’s dive in!

An overview of the Ishikawa diagram

What are fishbone diagrams used for?

This diagram was created by Professor Kaoru Ishikawa to make brainstorming sessions more effective at conducting a thorough root cause analysis. After the project team has discussed a problem, it is used to sort all the ideas into categories.

Using this visualisation allows your team to:

  • Take a step back and think about a phenomenon or challenge,
  • Communicate and share ideas more effectively,
  • Make decisions more quickly.
edrawmax-fishbone-diagram© Project Management Skills

How does a fishbone diagram work?

What makes this tool a favourite of project managers and quality professionals is its ease of use. It is simply read from left to right and can be used to collaborate with others on problem-solving.

This visual representation resembles fishbones and helps analyse the causes and consequences of a given problem. Therefore, some may call it a cause and effect diagram:

  • The fishbones are oriented on the left-hand side and represent the causes,
  • The head of the fish represents the final effect of the problem.

How to build an Ishikawa diagram in 5 steps

Step 1: Find the problem statement

Start by identifying the “effect” to study. More often than not, it is a problem to solve, but it can also be a need to meet or an objective to reach. Describe the topic simply and objectively using metrics. You may use the SMART method to do so.

🔍 Examples of problematic effects:

  • Decreasing margin,
  • Online traffic slowing down,
  • High turnover...

Step 2: Brainstorm to think of the main causes of the problem

The next step is to list all the contributing factors that could possibly be at play and ultimately produce the adverse effect.

To get the most comprehensive list possible, conduct a brainstorming session together with your team. Be sure to include diverse sets of skills and points of view: invite people from different backgrounds or departments to help you see all the angles. Your collaborative effort should help you find both the main causes of the problem and all the secondary factors.

🔍 For example, a decreasing margin could be caused by:

  • Poor pricing policy,
  • More intense competition on the market,
  • Frequent special offers…

💡 Our tip: you can use the “5 whys” method to find the root cause of the problem. For each cause, ask yourself the question “Why?” 5 times. After 5 rounds, the root factor is usually reached.


Category: Man

Problem: salespeople lack motivation

1. Why?

Because some performance bonuses have been discontinued.

2. Why?

Because sales objectives have not been met.

3. Why?

Because there is a lack of sales tools.

4. Why?

Because no budget was allocated to buying efficient sales software.

5. Why?

Because it was decided to recruit new salespeople rather than invest in tools.

Step 3: Sort these causes into categories

As you may have noticed in the table above, each problem belongs to a certain category. Each category is represented by a fishbone coming out of the “spine” of the fish, in other words from the central arrow.

Categorising your causes helps you not miss out on specific aspects of the problem. Though these general categories may vary widely depending on the nature of the problem, your industry, the size of your company and more, there are some methods that can serve as useful sorting techniques.

The 4S diagram

This simple categorisation method uses 4 main categories:

  • Surroundings,
  • Suppliers,
  • Skills,
  • Systems.

It is especially useful when tackling supply chain problems, or other general problems and shortages in the manufacturing industry.

The 5M-1E fishbone diagram

This set of categories is probably the most widely used. It is flexible enough to remain general, yet it allows for a comprehensive approach to most problems. It comprises 6 basic categories:

  • Man: it regroups all kinds of causes linked to your workforce or colleagues (lack of training, motivation…),
  • Machine: this category is dedicated to technical problems or problems with your tools,
  • Method: this group refers to organisational problems caused by inefficient processes or work methodologies,
  • Material: these causes could be shortages, quality problems with suppliers, or anything that could impact the production process,
  • Measurement: these causes are often improper evaluation of the workload, lack of insight or general visibility due to inefficient KPIs or inaccurate metrics,
  • Environment: these are the causes that are external to your company, such as new legislation, changes in the market and more.

💡 Feel free to imagine your own categories! What matters is that they are adapted to your specific problem: there are no rules. For less complex problems and when maximum flexibility is needed, you may even skip the use of categories altogether and list the causes directly onto the arrows linked to the spine.

Step 4: Identify the branches that have the most impact

This step aims at analysing the different categories to define their importance. It is crucial to prioritise them before springing into action:

  • Annotate each branch with your prioritisation system of choice, for example, a scale from 0 to 5, or from --- to +++,
  • This should help you define the order to follow when taking action to solve the problem, and will help you create the project plan and project schedule.

Step 5: Draw the Ishikawa diagram

The diagram serves as the synthesis of your reflection. Its main purpose is to make sure you do not overlook any aspect of the problem or neglect to analyse parts of the issue. You can draw the fishbone diagram on a blank sheet of paper in 5 steps:

  1. Draw a horizontal arrow going from left to right,
  2. Define the categories and draw the fishbones from the horizontal line,
  3. Group the different causes under the relevant category,
  4. Draw a line on the relevant category fishbone for each cause,
  5. If necessary, do the same for causes that may have underlying sub-factors.

After completing this diagram, you should be ready to move on to the next phase of your project! You can use other useful tools such as the Gantt chart to organise your workload and plan tasks.

Example: free fishbone diagram template

To help you build your own Ishikawa diagram, feel free to use our free fishbone diagram template. It contains reminders to guide you through the building process as well as example categories for you to use when sorting out the causes of the problem.

Using the Ishikawa diagram for quality control in project management

Using the fishbone diagram and the 5W1E method can be of great help in a variety of situations and for problem-solving at large. When the Ishikawa diagram is used in project management, it can lead to important quality improvements and corrective measures, as it allows you to go to the root cause of the issue and solve the problem for good. You could bring down costs, improve employee productivity and more!

Collaborating with your team and organising your ideas with this simple tool can yield impressive results! Are you ready to embrace the Ishikawa method? Have you used a fishbone diagram before, and if so, did it help? Feel free to share your experience below!

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